Project Summary/Abstract (30 lines): Many individuals with psychotic disorders report having experienced subthreshold clinical high risk (CHR) symptoms in adolescence. Identification and engagement of youth in early stages of psychosis can facilitate symptom monitoring, and early treatment maximizes recovery. The purpose of this study is to identify psychiatrically hospitalized adolescents who present with new-onset CHR symptoms and enroll them and their caregivers in a brief treatment engagement intervention. The specific aims are to: 1) develop a brief family-based intervention and pilot the intervention in a randomized control trial (RCT); 2) evaluate the engagement of therapeutic mechanisms presumed to underlie the intervention; and 3) evaluate the relations between the proposed mechanisms and service use. The proposed intervention includes three evidence-based modules: assessment, psychoeducation, and motivational enhancement. Three purported underlying mechanisms will be targeted: mental health literacy, attitudes toward treatment, and family partnership. Content will be reinforced after discharge using an existing mobile platform designed to enhance the scope and reach of the intervention (e.g., track referrals, monitor symptoms, and provide ongoing access to materials). In order to develop and adapt the intervention to the inpatient setting, evidence-based content will be piloted with identified teens and parents, and qualitative interviews will be conducted to explore opinions regarding intervention content and delivery. This pilot will be conducted with parents and teens (n = 16-30 dyads) using an iterative approach to finalize content. Next, an RCT will be conducted with a larger sample (n = 80 dyads), and outcomes, measured at 1- and 3-month follow-ups, will be compared to a treatment-as-usual group. Primary outcomes will be engagement of the purported therapeutic mechanisms (i.e. mental health literacy, attitudes toward treatment, family partnership). Secondary outcomes include outpatient service use and completion of referral to the state?s coordinated specialty care (CSC) clinic, an early psychosis program offering outpatient case management to support service transitions and ongoing monitoring. The broad goals of this study are to evaluate the feasibility and acceptability of the brief intervention, and to explore the intervention?s engagement of mechanisms and influence on service use outcomes. The proposed study is innovative because it offers specialized intervention for CHR starting on an adolescent inpatient unit and continuing after discharge with a symptom monitoring family support program. The novel intervention program may enhance linkage to ongoing mental health care, a step that is crucial for improving CHR outcomes.